The Governor of California, Jerry Brown, has issued an executive order to cut greenhouse gas emissions 40% from 1990 levels by 2030 (a 44% cut on 2012 levels). This matches the target set by the EU. It is tougher than that of the US administration, which has set a target of reducing emissions in the range of 26 to 28 percent below 2005 levels by 2025.

The former Governor of California, Arnold Schwarzenegger, had previously set a target of reducing emissions 80% below 1990 levels by 2050. Brown’s new target can be seen as an interim step toward meeting that longer-term goal.

There are several means by which it is planned to meet the Californian targets. These include:

a focus on zero- and near-zero technologies for moving freight, continued investment in renewables including solar roofs and distributed generation, greater use of low-carbon fuels including electricity and hydrogen, stronger efforts to reduce emissions of short-lived climate pollutants (methane, black carbon and fluorinated gases), and further efforts to create liveable, walkable communities and expansion of mass transit and other alternatives to travelling by car.

Some of these will be achieved through legislation, after consultations with various stakeholders. But a crucial element in driving down emissions is the California’s carbon trading scheme. This is a cap-and-trade system, similar to the EU’s Emissions Trading Scheme.

The cap-and-trade rules came into effect on January 1, 2013 and apply to large electric power plants and large industrial plants. In 2015, they will extend to fuel distributors (including distributors of heating and transportation fuels). At that stage, the program will encompass around 360 businesses throughout California and nearly 85 percent of the state’s total greenhouse gas emissions.

Under a cap-and-trade system, companies must hold enough emission allowances to cover their emissions, and are free to buy and sell allowances on the open market. California held its first auction of greenhouse gas allowances on November 14, 2012. This marked the beginning of the first greenhouse gas cap-and-trade program in the United States since the group of nine Northeastern states in the Regional Greenhouse Gas Initiative (RGGI), a greenhouse gas cap-and-trade program for power plants, held its first auction in 2008.

Since January 2014, the Californian cap-and-trade scheme has been linked to that of Quebec in Canada and discussions are under way to link it with Ontario too. Also California is working with other west-coast states/provinces, Oregon, Washington and British Columbia, to develop a co-ordinated approach to greenhouse gas reductions

To achieve sufficient reductions in emissions, it is not enough merely to have a cap-and-trade system which, through trading, encourages an efficient reduction in emissions. It is important to set the cap tight enough to achieve the targeted reductions and to ensure that the cap is enforced.

In California, emissions allowances are distributed by a mix of free allocation and quarterly auctions. Free allocations account for around 90% of the allocations, but this percentage will decrease over time. The total allowances will decline (i.e. the cap will be tightened) by 3% per year from 2015 to 2020.

At present the system applies to electric power plants, industrial plants and fuel distributors that emit, or are responsible for emissions of, 25,000 metric tons of carbon dioxide equivalent (CO2e) per year or more. The greenhouse gases covered are the six covered by the Kyoto Protocol ((CO2, CH4, N2O, HFCs, PFCs, SF6), plus NF3 and other fluoridated greenhouse gases.